.main {
    width: 500px;
    height:400px;
    margin:0 auto;
}
.main .btn {
    width:60px;
    height:32px;
    line-height: 32px;
    background-color: blueviolet;
    text-align: center;
    color: #fff;
    border-radius:5px;
    margin-top:3em;
}